This circuit uses a high brightness LED to simulate a LASER. We found it in a 1991s PE Hobbyst Handbook. The components used are all common.
This experimental amplifier was found in the 1960 Mullard transistor reference manual. The...
This circuit from Motorola is from 1968, appearing elsewhere on this site. The transistors admit...
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...